ML092650387
| ML092650387 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 09/11/2009 |
| From: | Bezilla M FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-09-122 | |
| Download: ML092650387 (25) | |
Text
FENOC Perry Nuclear Power Station 10 Center Road FirstEnergy Nuclear Operating Company Perry, Ohio 44081 Mark B. Bezilla 440-280-5382 Vice President Fax: 440-280-8029 September 11, 2009 L-09-122 10 CFR 50.55a ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant Docket No. 50-440, License No. NPF-58 Flaw Evaluation for N6A and C Nozzle-To-Safe-End Welds In letters dated August 2, 1999 and June 18, 2001, inservice inspection (ISI) summary reports were submitted by FirstEnergy Nuclear Operating Company (FENOC) to the Nuclear Regulatory Commission (NRC) after the respective refueling outages at the Perry Nuclear Power Plant (PNPP) in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section Xl, "Inservice Inspection", 1989 Edition, Article IWA-6000. All indications were evaluated for acceptance in accordance with ASME Section XI, Article IWA-3000 and all required corrective actions and evaluations were completed.
In September 2008, under Boiling Water Reactor Vessel and Internals Project (BWRVIP) guidance, FENOC completed a review of previous dissimilar metal weld examination data that had not yet been evaluated using the new ASME Section Xl, Appendix VIII, Supplement 10 requirements. This review included examination data for Feedwater (N4), Core Spray (N5), and Residual Heat Removal (N6) nozzle-to-safe-end welds examined in the refueling outages of 1999 and 2001. The review identified two unacceptable indications in the N6A and one unacceptable indication in the N6C nozzle-to-safe-end welds. These three unacceptable indications were determined to be subsurface flaws that exceed ASME Section XI subsurface flaw acceptance criteria. FENOC submitted (letter dated January 19, 2009) an evaluation of the fabrication defects performed in accordance with ASME Section Xl, Article IWB-3600. The welds were deemed acceptable for continued service without flaw removal, repair, or replacement through the spring 2009 refueling outage.
The ISI examinations conducted during the spring 2009 refueling outage identified a change in reported indication length for the N6C nozzle-to-safe-end weld. The unacceptable indication reported by FENOC in January 2009 for N6C was approximately 11 inches in length. An additional acceptable indication of approximately 2 inches in length existed in close proximity to the unacceptable FENOC FirstEnergy Nuclear Operating Company Mark B. Bezilla Vice President September 11,2009 L-09-122 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant Docket No. 50-440, License No. NPF-58 Flaw Evaluation for N6A and C Nozzle-To-Safe-End Welds Perry Nuclear Power Station 10 Center Road Perry, Ohio 44081 440-280-5382 Fax.- 440-280-8029 10 CFR 50.55a In letters dated August 2, 1999 and June 18, 2001, inservice inspection (lSI) summary reports were submitted by FirstEnergy Nuclear Operating Company (FENOC) to the Nuclear Regulatory Commission (NRC) after the respective refueling outages at the Perry Nuclear Power Plant (PNPP) in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Inservice Inspection", 1989 Edition, Article IWA-6000. All indications were evaluated for acceptance in accordance with ASME Section XI, Article IWA-3000 and all required corrective actions and evaluations were completed.
In September 2008, under Boiling Water Reactor Vessel and Internals Project (BWRVIP) guidance, FENOC completed a review of previous dissimilar metal weld examination data that had not yet been evaluated using the new ASME Section XI, Appendix VIII, Supplement 10 requirements. This review included examination data for Feedwater (N4), Core Spray (N5), and Residual Heat Removal (N6) nozzle-to-safe-end welds examined in the refueling outages of 1999 and 2001. The review identified two unacceptable indications in the N6A and one unacceptable indication in the N6C nozzle-to-safe-end welds. These three unacceptable indications were determined to be subsurface flaws that exceed ASME Section XI subsurface flaw acceptance criteria. FENOC submitted (letter dated January 19, 2009) an evaluation of the fabrication defects performed in accordance with ASME Section XI, Article IWB-3600. The welds were deemed acceptable for continued service without flaw removal, repair, or replacement through the spring 2009 refueling outage.
The lSI examinations conducted during the spring 2009 refueling outage identified a change in reported indication length for the N6C nozzle-to-safe-end weld. The unacceptable indication reported by FENOC in January 2009 for N6C was approximately 11 inches in length. An additional acceptable indication of approximately 2 inches in length existed in close proximity to the unacceptable
Perry Nuclear Power Plant L-09-122 Page 2 indication. The spring 2009 ISI examinations revealed these two indications as one continuous indication with a total length of 16.6 inches. This length exceeds the bounding flaw size previously evaluated and exceeds ASME Section Xl subsurface flaw acceptance criteria. As a result, a bounding evaluation (Enclosure) was performed in accordance with ASME Section XI, Article IWB-3600, to determine the acceptability of continued service of the weld through the next scheduled inspection interval.
The ISI examinations also revealed that one of the unacceptable indications reported by FENOC in January 2009 for N6A nozzle-to-safe-end welds was acceptable due a slightly lower through wall measurement recorded in 2009. A bounding evaluation (Enclosure) for the remaining unacceptable indication was performed in accordance with ASME Section XI, Article IWB-3600, to determine the-acceptability of continued service of the weld through the next scheduled inspection interval.
As concluded in the evaluation, the reported subsurface flaws and the projected growth due to fatigue do not reduce the capacity of the N6A and N6C nozzle-to-safe-end welds below Code allowables. All Code margins are maintained. Therefore, the welds are acceptable for continued service without the flaw removal, repair, or replacement through the next scheduled inspection interval.
In accordance with 10 CFR 50.55a and ASME Section Xl, Article IWB-3134, FENOC hereby submits the evaluation (Enclosure) of the fabrication defects in PNPP's N6A and N6C nozzle-to-safe-end welds.
There are no regulatory commitments contained in this letter. If there are any questions, or if additional information is required, please contact Mr. Thomas A. Lentz, Manager - Fleet Licensing, at (330) 761-6071.
Sincerely, Mark B. Bezilla
Enclosure:
Flaw Evaluation for N6A and C Nozzle to Safe End Welds cc: NRC Region III Administrator NRC Resident Inspector Nuclear Reactor Regulation Project Manager Perry Nuclear Power Plant L-09-122 Page 2 indication. The spring 2009 lSI examinations revealed these two indications as one continuous indication with a total length of 16.6 inches. This length exceeds the bounding flaw size previously evaluated and exceeds ASME Section XI subsurface flaw acceptance criteria. As a result, a bounding evaluation (Enclosure) was performed in accordance with ASME Section XI, ArtiCle IWB-3600, to determine the acceptability of continued service of the weld through the next scheduled inspection interval.
The lSI examinations also revealed that one of the unacceptable indications reported by FENOC in January 2009 for N6A nozzle-to-safe-end welds was acceptable due a slightly lower through wall measurement recorded in 2009. A bounding evaluation (Enclosure) for the remaining unacceptable indication was performed in accordance with ASME Section XI, Article IWB-3600, to determine the' acceptability of continued service of the weld through the next scheduled inspection interval.
As concluded in the evaluation, the reported subsurface flaws and the projected growth due to fatigue do not reduce the capacity of the N6A and N6C nozzle-to-safe-end welds below Code allowables. All Code margins are maintained. Therefore, the welds are acceptable for continued service without the flaw removal, repair, or replacement through the next scheduled inspection interval.
In accordance with 10 CFR 50.55a and ASME Section XI, Article IWB-3134, FENOC hereby submits the evaluation (Enclosure) of the fabrication defects in PNPP's N6A and N6C nozzle-to-safe-end welds.
There are no regulatory commitments contained in this letter. If there are any questions, or if additional information is required, please contact Mr. Thomas A. Lentz, Manager - Fleet Licensing, at (330) 761-6071.
Sincerely,
~
Mark B. Bezilla
Enclosure:
Flaw Evaluation for N6A and C Nozzle to Safe End Welds cc: NRC Region III Administrator NRC Resident Inspector Nuclear Reactor Regulation Project Manager
Enclosure L-09-122 Flaw Evaluation for N6A and C Nozzle to Safe End Welds (22 pages follow)
Enclosure L-09-122 Flaw Evaluation for N6A and C Nozzle to Safe End Welds (22 pages follow)